Elena Ballesteros was selected for a role in this series, but she didn't accept because she had another projects.

'Merce Pons' was pregnant while filming season six.

The school of the series is called Colegio Azcona and the bar where the main characters often go is La Escapada.

Lara de Miguel left "Querido maestro" in order to join the cast of Compañeros.

Manuel Feijóo is the only member of the main gang who appeared in all the seasons of the series and almost in all the episodes.

Although they were regular cast members, Pilar Punzano, Irene García, Rebeca Cobos and Tito Augusto were never included in the opening credits.

The character of Emilio were performed by three different actors: first Jorge San José later Juan José Ballesta and finally Daniel Esparza.

Lola Baldrich and Francis Lorenzo had worked together before in Médico de familia.

Beatriz Carvajal' and Montse Pla are mother and daughter in real life.

Pilar Bayona, who played Leo's mum, is Alba Alonso's mother in real life.